1. Field of the Invention
The present invention relates to a disc drive apparatus capable of carrying out reproduction or recording in accordance with a plurality of disc type recording media.
2. Description of Related Art
As an optical disc recording medium, compact discs (CD) are widely used for music and other fields. A compact disc for music is normally used only as a reproduction medium. However, a compact disc recordable (CD-R) is also being developed. This is a disc into which additional data can be written.
A disc called DVD (digital versatile disc/digital video disc) is also being developed as an optical disc recording medium for multimedia use. The DVD is expected to be applied to a wide range of fields such as video data, audio data, and computer data. Although a DVD is the same as a CD in size (diameter of 12 cm), a recording capacity is remarkably increased by means of reduction in recording track pitch and data compression technique.
Corresponding to the development of a novel disc, it is desired to provide a disc drive apparatus having a compatibility with a conventional disc.
For example, it is desired to develop a disc drive apparatus which answers both to the CD and DVD. However, because of the difference in their layered structures, each of the CD and the DVD requires a specific pickup device (or a block of an optical section in a pickup device). When a disc is mounted, it should be identified as a CD or DVD, and a corresponding block should be set in for use.
When specific blocks are switched corresponding to a plurality of types of disc, it is necessary to accurately identify the type of a disc which is mounted on the apparatus.
For example, in a case when a disc is contained in a cartridge, the type of the disc can easily be identified by preparing an identification hole on the cartridge. However, this method cannot be applied to a disc which is not contained in a cartridge such as CD and DVD. Moreover, when discs have an identical size, no mechanical detection method can be applied.
Furthermore, it is not preferable to provide a particular component or mechanism for disc type detection such as a sensor because the apparatus configuration becomes complicated and costs are increased.